It is possible to nest a bulleted-unnumbered list into a higher numbered list.
But in the bulleted-unnumbered list the automatically numbered list will not start: Its is not supported.
To start a new numbered list after a bulleted-unnumbered one, put a piece of text between them, or a subtitle: A new numbered list cannot start just behind the bulleted: The interpreter will not start the numbering.
in practice
Dog
German Shepherd - with only a single space ahead.
Belgian Shepherd - max 4 spaces ahead.
Number in front of a line interpreted as a "numbering bullet", so making the indentation.
..and ignores the written digit: Places/generates its own, in compliance with the structure.
So it is OK to use only just "1" ones, to get your numbered list.
Or whatever integer number, even of more digits: The list numbering will continue by increment ++1.
However, the first item in the numbered list will be kept, so the first leading will usually be the number "1".
Malinois - 5 spaces makes 3rd level already.
MalinoisB - 5 spaces makes 3rd level already.
Groenendael - 8 spaces makes 3rd level yet too.
Tervuren - 9 spaces for 4th level - Intentionaly started by "55".
TervurenB - numbered by "88", in the source code.
Cat
Siberian;
a. SiberianA - problem reproduced: letters (i.e. "a" here) not recognized by the interpreter as "numbering".
No matter, it is indented to its separated line, in the source code.
Siamese
a. so written manually as a workaround misusing bullets, unnumbered list.